[BUG](fn-consumer): Skip stale work fetch

[tanujnay112]

Summary

Avoid materializing logs for stale async attached-function queue records, and explicitly acknowledge records that are already complete at the current collection head.

Root cause

fn-consumer fetched and materialized every input collection before comparing the attached-function completion frontier with the queued compaction frontier. A stale input could therefore load millions of records and then be discarded.

Change

• Look up the current attached-function completion frontier in SysDB before fetching logs.
• When that completion offset equals the collection head and is at or beyond the queued frontier, call FinishWork directly. This advances/records the invocation frontier and removes the queue item without boundary resolution or function execution.
• When the completion offset is behind the collection head, leave the work queued for the existing boundary-resolution/execution path.
• Keep the existing post-fetch check as a race-safety guard.

Validation

• cargo test -p worker function_execution --lib

[github-actions]

Reviewer Checklist

Please leverage this checklist to ensure your code review is thorough before approving

Testing, Bugs, Errors, Logs, Documentation

• Can you think of any use case in which the code does not behave as intended? Have they been tested?
• Can you think of any inputs or external events that could break the code? Is user input validated and safe? Have they been tested?
• If appropriate, are there adequate property based tests?
• If appropriate, are there adequate unit tests?
• Should any logging, debugging, tracing information be added or removed?
• Are error messages user-friendly?
• Have all documentation changes needed been made?
• Have all non-obvious changes been commented?

System Compatibility

• Are there any potential impacts on other parts of the system or backward compatibility?
• Does this change intersect with any items on our roadmap, and if so, is there a plan for fitting them together?

Quality

• Is this code of a unexpectedly high quality (Readability, Modularity, Intuitiveness)

[claude]

Claude Code Review

This repository is configured for manual code reviews. Comment @claude review for a one-time review, or @claude review always to subscribe this PR to a review on every future push.

_{Tip: disable this comment in your organization's Code Review settings.}

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: d02a95ce40

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

Avoid the single-ID SysDB request that always errors

Every fn-consumer batch now reaches this lookup before fetching logs, but GrpcSysDb::get_attached_functions encodes a one-element ids vector into both the deprecated id field and the ids field (rust/sysdb/src/sysdb.rs:2451-2464). The coordinator explicitly rejects requests containing both fields (go/pkg/sysdb/coordinator/task.go:928-930), so in the production gRPC SysDB configuration this returns InvalidArgument for every work item and prevents all async attached-function execution. Use a lookup that populates only one of those fields, or correct the helper before calling it here.

Useful? React with 👍 / 👎.